git.delta.rocks / jrsonnet / refs/commits / 79b689b0a354

1use std::alloc::{GlobalAlloc, Layout};2use std::borrow::Cow;3use std::cell::RefCell;4use std::ffi::{CStr, CString, c_char, c_int, c_uint, c_void};5use std::mem::forget;6use std::ptr::null_mut;7use std::sync::LazyLock;8use std::{collections::HashMap, path::PathBuf};9use std::{fmt, slice};1011use anyhow::{Context, anyhow, bail};12use serde::Serialize;13use serde::de::DeserializeOwned;1415pub use anyhow::Result;16use tracing::{info, instrument};1718use self::logging::nix_logging_cxx;19use self::nix_cxx::set_fetcher_setting;20use self::nix_raw::{21	BindingsBuilder as c_bindings_builder, EvalState as c_eval_state, GC_SUCCESS,22	GC_allow_register_threads, GC_free, GC_get_stack_base, GC_init, GC_malloc, GC_realloc,23	GC_register_my_thread, GC_stack_base, GC_thread_is_registered, GC_unregister_my_thread,24	Store as c_store, alloc_value, bindings_builder_free, bindings_builder_insert, c_context,25	c_context_create, c_context_free, clear_err, err_code, err_info_msg, err_msg, eval_state_build,26	eval_state_builder_load, eval_state_builder_new, eval_state_builder_set_eval_setting,27	expr_eval_from_string, fetchers_settings, fetchers_settings_free, fetchers_settings_new,28	flake_lock, flake_lock_flags, flake_lock_flags_free, flake_lock_flags_new, flake_reference,29	flake_reference_and_fragment_from_string, flake_reference_parse_flags,30	flake_reference_parse_flags_free, flake_reference_parse_flags_new,31	flake_reference_parse_flags_set_base_directory, flake_settings, flake_settings_free,32	flake_settings_new, get_attr_byname, get_attr_name_byidx, get_attrs_size, get_list_byidx,33	get_list_size, get_string, get_type, has_attr_byname, init_bool, init_int, init_string,34	libexpr_init, libstore_init, libutil_init, locked_flake, locked_flake_free,35	locked_flake_get_output_attrs, make_attrs, make_bindings_builder, realised_string,36	realised_string_free, realised_string_get_buffer_size, realised_string_get_buffer_start,37	realised_string_get_store_path, realised_string_get_store_path_count, set_err_msg, setting_set,38	state_free, store_open, store_path_name, string_realise, value, value_call, value_decref,39	value_incref,40};4142// Contains macros helpers43pub mod logging;44#[doc(hidden)]45pub mod macros;46pub mod util;4748#[allow(49	non_upper_case_globals,50	non_camel_case_types,51	non_snake_case,52	dead_code53)]54mod nix_raw {55	include!(concat!(env!("OUT_DIR"), "/bindings.rs"));56}57#[cxx::bridge]58pub mod nix_cxx {59	unsafe extern "C++" {60		type nix_fetchers_settings;61		include!("nix-eval/src/lib.hh");6263		unsafe fn set_fetcher_setting(64			settings: *mut nix_fetchers_settings,65			setting: *const c_char,66			value: *const c_char,67		);68	}69}7071#[derive(Debug, PartialEq, Eq)]72pub enum NixType {73	Thunk,74	Int,75	Float,76	Bool,77	String,78	Path,79	Null,80	Attrs,81	List,82	Function,83	External,84}85impl NixType {86	fn from_int(c: c_uint) -> Self {87		match c {88			0 => Self::Thunk,89			1 => Self::Int,90			2 => Self::Float,91			3 => Self::Bool,92			4 => Self::String,93			5 => Self::Path,94			6 => Self::Null,95			7 => Self::Attrs,96			8 => Self::List,97			9 => Self::Function,98			10 => Self::External,99			_ => unreachable!("unknown nix type: {c}"),100		}101	}102}103104enum FunctorKind {105	Function,106	Functor,107}108109#[derive(Debug)]110#[repr(i32)]111pub enum NixErrorKind {112	Unknown = 1,113	Overflow = 2,114	Key = 3,115	Generic = 4,116}117impl NixErrorKind {118	fn from_int(v: c_int) -> Option<Self> {119		Some(match v {120			0 => return None,121			-1 => Self::Unknown,122			-2 => Self::Overflow,123			-3 => Self::Key,124			-4 => Self::Generic,125			_ => {126				debug_assert!(false, "unexpected nix error kind: {v}");127				Self::Unknown128			}129		})130	}131}132133pub fn gc_now() {134	unsafe { nix_raw::gc_now() };135}136137pub fn gc_register_my_thread() {138	assert_eq!(unsafe { GC_thread_is_registered() }, 0);139140	let mut sb = GC_stack_base {141		mem_base: null_mut(),142	};143	let r = unsafe { GC_get_stack_base(&mut sb) };144	if r as u32 != GC_SUCCESS {145		panic!("failed to get thread stack base");146	}147	unsafe { GC_register_my_thread(&sb) };148}149pub fn gc_unregister_my_thread() {150	assert_eq!(unsafe { GC_thread_is_registered() }, 1);151152	unsafe { GC_unregister_my_thread() };153}154155pub struct ThreadRegisterGuard {}156impl ThreadRegisterGuard {157	#[allow(clippy::new_without_default)]158	pub fn new() -> Self {159		gc_register_my_thread();160		Self {}161	}162}163impl Drop for ThreadRegisterGuard {164	fn drop(&mut self) {165		gc_unregister_my_thread();166	}167}168169pub struct NixContext(*mut c_context);170impl NixContext {171	pub fn set_err(&mut self, err: NixErrorKind, msg: &CStr) {172		unsafe { set_err_msg(self.0, err as c_int, msg.as_ptr()) };173	}174	pub fn new() -> Self {175		let ctx = unsafe { c_context_create() };176		Self(ctx)177	}178	fn error_kind(&self) -> Option<NixErrorKind> {179		let code = unsafe { err_code(self.0) };180		NixErrorKind::from_int(code)181	}182	fn error<'t>(&self) -> Option<Cow<'t, str>> {183		if let NixErrorKind::Generic = self.error_kind()? {184			let mut err_out = String::new();185			unsafe {186				err_info_msg(187					null_mut(),188					self.0,189					Some(copy_nix_str),190					(&raw mut err_out).cast(),191				)192			};193			return Some(Cow::Owned(err_out));194		};195196		// TODO: Can throw error (resulting in panic) if unable to retrieve error. Should be able to resolve by passing context as a first argument,197		// but it looks ugly198		let str = unsafe { err_msg(null_mut(), self.0, null_mut()) };199		Some(unsafe { CStr::from_ptr(str) }.to_string_lossy())200	}201	fn clean_err(&mut self) {202		unsafe {203			clear_err(self.0);204		}205	}206207	fn bail_if_error(&self) -> Result<()> {208		if let Some(err) = self.error() {209			bail!("{err}");210		};211		Ok(())212	}213214	fn run_in_context<T>(&mut self, f: impl FnOnce(*mut c_context) -> T) -> Result<T> {215		self.clean_err();216		let o = f(self.0);217		self.bail_if_error()?;218		self.clean_err();219		Ok(o)220	}221}222223impl Default for NixContext {224	fn default() -> Self {225		Self::new()226	}227}228impl Drop for NixContext {229	fn drop(&mut self) {230		unsafe {231			c_context_free(self.0);232		}233	}234}235struct GlobalState {236	// Store should be valid as long as EvalState is valid237	#[allow(dead_code)]238	store: Store,239	state: EvalState,240}241impl GlobalState {242	fn new() -> Result<Self> {243		let mut ctx = NixContext::new();244		let store = ctx245			.run_in_context(|c| unsafe { store_open(c, c"auto".as_ptr(), null_mut()) })246			.map(Store)?;247248		let builder = ctx.run_in_context(|c| unsafe { eval_state_builder_new(c, store.0) })?;249		ctx.run_in_context(|c| unsafe { eval_state_builder_load(c, builder) })?;250		ctx.run_in_context(|c| unsafe {251			eval_state_builder_set_eval_setting(252				c,253				builder,254				c"lazy-trees".as_ptr(),255				c"true".as_ptr(),256			)257		})?;258		ctx.run_in_context(|c| unsafe {259			eval_state_builder_set_eval_setting(260				c,261				builder,262				c"lazy-locks".as_ptr(),263				c"true".as_ptr(),264			)265		})?;266		let state = ctx267			.run_in_context(|c| unsafe { eval_state_build(c, builder) })268			.map(EvalState)?;269270		Ok(Self { store, state })271	}272}273274struct ThreadState {275	ctx: NixContext,276}277impl ThreadState {278	fn new() -> Result<Self> {279		let ctx = NixContext::new();280281		Ok(Self { ctx })282	}283}284285static GLOBAL_STATE: LazyLock<GlobalState> =286	LazyLock::new(|| GlobalState::new().expect("global state init shouldn't fail"));287288thread_local! {289	static THREAD_STATE: RefCell<ThreadState> = RefCell::new(ThreadState::new().expect("thread state init shouldn't fail"));290}291fn with_default_context<T>(f: impl FnOnce(*mut c_context, *mut c_eval_state) -> T) -> Result<T> {292	let global = &GLOBAL_STATE.state;293	let (ctx, state) = THREAD_STATE.with_borrow_mut(|w| (w.ctx.0, global.0));294	let mut ctx = NixContext(ctx);295	let v = ctx.run_in_context(|c| f(c, state));296	// It is reused for thread297	std::mem::forget(ctx);298	v299}300301pub fn set_setting(s: &CStr, v: &CStr) -> Result<()> {302	with_default_context(|c, _| unsafe { setting_set(c, s.as_ptr(), v.as_ptr()) }).map(|_| ())303}304305pub struct FetchSettings(*mut fetchers_settings);306impl FetchSettings {307	pub fn new() -> Self {308		Self::try_new().expect("allocation should not fail")309	}310	fn try_new() -> Result<Self> {311		with_default_context(|c, _| unsafe { fetchers_settings_new(c) }).map(Self)312	}313	pub fn set(&mut self, setting: &CStr, value: &CStr) {314		unsafe {315			set_fetcher_setting(self.0.cast(), setting.as_ptr(), value.as_ptr());316		};317	}318}319unsafe impl Send for FetchSettings {}320unsafe impl Sync for FetchSettings {}321322impl Default for FetchSettings {323	fn default() -> Self {324		Self::new()325	}326}327328impl Drop for FetchSettings {329	fn drop(&mut self) {330		unsafe { fetchers_settings_free(self.0) };331	}332}333pub struct FlakeSettings(*mut flake_settings);334impl FlakeSettings {335	pub fn new() -> Result<Self> {336		with_default_context(|c, _| unsafe { flake_settings_new(c) }).map(Self)337	}338}339unsafe impl Send for FlakeSettings {}340unsafe impl Sync for FlakeSettings {}341impl Drop for FlakeSettings {342	fn drop(&mut self) {343		unsafe {344			flake_settings_free(self.0);345		}346	}347}348349pub struct FlakeReferenceParseFlags(*mut flake_reference_parse_flags);350impl FlakeReferenceParseFlags {351	pub fn new(settings: &FlakeSettings) -> Result<Self> {352		with_default_context(|c, _| unsafe { flake_reference_parse_flags_new(c, settings.0) })353			.map(Self)354	}355	pub fn set_base_dir(&mut self, dir: &str) -> Result<()> {356		with_default_context(|c, _| {357			unsafe {358				flake_reference_parse_flags_set_base_directory(359					c,360					self.0,361					dir.as_ptr().cast(),362					dir.len(),363				)364			};365		})366	}367}368impl Drop for FlakeReferenceParseFlags {369	fn drop(&mut self) {370		unsafe {371			flake_reference_parse_flags_free(self.0);372		}373	}374}375pub struct FlakeLockFlags(*mut flake_lock_flags);376impl FlakeLockFlags {377	pub fn new(settings: &FlakeSettings) -> Result<Self> {378		let o = with_default_context(|c, _| unsafe { flake_lock_flags_new(c, settings.0) })379			.map(Self)?;380		// with_default_context(|c, _| unsafe { flake_lock_flags_set_mode_virtual(c, o.0) })?;381382		Ok(o)383	}384}385impl Drop for FlakeLockFlags {386	fn drop(&mut self) {387		unsafe {388			flake_lock_flags_free(self.0);389		}390	}391}392393unsafe extern "C" fn copy_nix_str(start: *const c_char, n: c_uint, user_data: *mut c_void) {394	let s = unsafe { slice::from_raw_parts(start.cast::<u8>(), n as usize) };395	let s = std::str::from_utf8(s).expect("c string has invalid utf-8");396	unsafe { *user_data.cast::<String>() = s.to_owned() };397}398399struct Store(*mut c_store);400unsafe impl Send for Store {}401unsafe impl Sync for Store {}402403struct EvalState(*mut c_eval_state);404unsafe impl Send for EvalState {}405unsafe impl Sync for EvalState {}406407impl Drop for EvalState {408	fn drop(&mut self) {409		unsafe {410			state_free(self.0);411		}412	}413}414415pub struct FlakeReference(*mut flake_reference);416impl FlakeReference {417	#[instrument(name = "new-flake-reference", skip(flake, parse, fetch))]418	pub fn new(419		s: &str,420		flake: &FlakeSettings,421		parse: &FlakeReferenceParseFlags,422		fetch: &FetchSettings,423	) -> Result<(Self, String)> {424		let mut out = null_mut();425		let mut fragment = String::new();426		// let fetch_settings = fetcher_settings;427		with_default_context(|c, _| unsafe {428			flake_reference_and_fragment_from_string(429				c,430				fetch.0,431				flake.0,432				parse.0,433				s.as_ptr().cast(),434				s.len(),435				&mut out,436				Some(copy_nix_str),437				(&raw mut fragment).cast(),438			)439		})?;440		assert!(!out.is_null());441442		Ok((Self(out), fragment))443	}444	#[instrument(name = "lock-flake", skip(self, fetch, flake, lock))]445	pub fn lock(446		&mut self,447		fetch: &FetchSettings,448		flake: &FlakeSettings,449		lock: &FlakeLockFlags,450	) -> Result<LockedFlake> {451		with_default_context(|c, es| unsafe { flake_lock(c, fetch.0, flake.0, es, lock.0, self.0) })452			.map(LockedFlake)453	}454}455unsafe impl Send for FlakeReference {}456unsafe impl Sync for FlakeReference {}457458pub struct LockedFlake(*mut locked_flake);459impl LockedFlake {460	pub fn get_attrs(&self, settings: &mut FlakeSettings) -> Result<Value> {461		with_default_context(|c, es| unsafe {462			locked_flake_get_output_attrs(c, settings.0, es, self.0)463		})464		.map(Value)465	}466}467unsafe impl Send for LockedFlake {}468unsafe impl Sync for LockedFlake {}469impl Drop for LockedFlake {470	fn drop(&mut self) {471		unsafe {472			locked_flake_free(self.0);473		};474	}475}476477type FieldName = [u8; 32];478fn init_field_name(v: &str) -> FieldName {479	let mut f = [0; 32];480	assert!(v.len() < 32, "max field name is 31 char");481	assert!(482		v.bytes().all(|v| v != 0),483		"nul bytes are unsupported in field name"484	);485	f[0..v.len()].copy_from_slice(v.as_bytes());486	f487}488489pub struct RealisedString(*mut realised_string);490impl fmt::Debug for RealisedString {491	fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {492		self.as_str().fmt(f)493	}494}495496impl RealisedString {497	pub fn as_str(&self) -> &str {498		let len = unsafe { realised_string_get_buffer_size(self.0) };499		let data: *const u8 = unsafe { realised_string_get_buffer_start(self.0) }.cast();500		let data = unsafe { slice::from_raw_parts(data, len) };501		std::str::from_utf8(data).expect("non-utf8 strings not supported")502	}503	pub fn path_count(&self) -> usize {504		unsafe { realised_string_get_store_path_count(self.0) }505	}506	pub fn path(&self, i: usize) -> String {507		assert!(i < self.path_count());508		let path = unsafe { realised_string_get_store_path(self.0, i) };509		let mut err_out = String::new();510		unsafe { store_path_name(path, Some(copy_nix_str), (&raw mut err_out).cast()) };511		err_out512	}513}514515unsafe impl Send for RealisedString {}516impl Drop for RealisedString {517	fn drop(&mut self) {518		unsafe { realised_string_free(self.0) }519	}520}521522pub struct Value(*mut value);523524unsafe impl Send for Value {}525unsafe impl Sync for Value {}526527pub trait AsFieldName {528	fn as_field_name<T>(&self, v: impl FnOnce(FieldName) -> Result<T>) -> Result<T>;529	fn to_field_name(&self) -> Result<String>;530}531impl AsFieldName for Value {532	fn as_field_name<T>(&self, v: impl FnOnce(FieldName) -> Result<T>) -> Result<T> {533		let f = self.to_string()?;534		v(init_field_name(&f))535	}536	fn to_field_name(&self) -> Result<String> {537		self.to_string()538	}539}540impl<E> AsFieldName for E541where542	E: AsRef<str>,543{544	fn as_field_name<T>(&self, v: impl FnOnce(FieldName) -> Result<T>) -> Result<T> {545		let f = self.as_ref();546		v(init_field_name(f))547	}548	fn to_field_name(&self) -> Result<String> {549		Ok(self.as_ref().to_owned())550	}551}552553struct AttrsBuilder(*mut c_bindings_builder);554impl AttrsBuilder {555	fn new(capacity: usize) -> Self {556		with_default_context(|c, es| unsafe { make_bindings_builder(c, es, capacity) })557			.map(Self)558			.expect("alloc should not fail")559	}560	fn insert(&mut self, k: &impl AsFieldName, v: Value) {561		k.as_field_name(|name| {562			with_default_context(|c, _| unsafe {563				bindings_builder_insert(c, self.0, name.as_ptr().cast(), v.0);564				// bindings_builder_insert doesn't do incref565			})566		})567		.expect("builder insert shouldn't fail");568	}569}570impl Drop for AttrsBuilder {571	fn drop(&mut self) {572		unsafe { bindings_builder_free(self.0) };573	}574}575576impl Value {577	pub fn new_attrs(v: HashMap<&str, Value>) -> Self {578		let out = Self::new_uninit();579		let mut b = AttrsBuilder::new(v.len());580		for (k, v) in v {581			b.insert(&k, v);582		}583		with_default_context(|c, _| unsafe { make_attrs(c, out.0, b.0) })584			.expect("attrs initialization should not fail");585586		out587	}588	fn new_list<T: Into<Self>>(v: Vec<T>) -> Self {589		todo!()590	}591	fn new_uninit() -> Self {592		let out = with_default_context(|c, es| unsafe { alloc_value(c, es) })593			.expect("value allocation should not fail");594		Self(out)595	}596	pub fn new_str(v: &str) -> Self {597		let s = CString::new(v).expect("string should not contain NULs");598		let out = Self::new_uninit();599		// String is copied, `s` is free to be dropped600		with_default_context(|c, _| unsafe { init_string(c, out.0, s.as_ptr()) })601			.expect("string initialization should not fail");602		out603	}604	pub fn new_int(i: i64) -> Self {605		let out = Self::new_uninit();606		with_default_context(|c, _| unsafe { init_int(c, out.0, i) })607			.expect("int initialization should not fail");608		out609	}610	pub fn new_bool(v: bool) -> Self {611		let out = Self::new_uninit();612		with_default_context(|c, _| unsafe { init_bool(c, out.0, v) })613			.expect("bool initialization should not fail");614		out615	}616	// TODO: As far as I can see, there is no way to get Thunks from nix public C api, so this function is useless617	// fn force(&mut self, st: &mut EvalState) -> Result<()> {618	// 	with_default_context(|c, _| unsafe { value_force(c, st.0, self.0) })?;619	// 	Ok(())620	// }621	pub fn type_of(&self) -> NixType {622		let ty = with_default_context(|c, _| unsafe { get_type(c, self.0) })623			.expect("get_type should not fail");624		NixType::from_int(ty)625	}626	fn builtin_to_string(&self) -> Result<Self> {627		let builtin = Self::eval("builtins.toString")?;628		builtin.call(self.clone())629	}630	pub fn to_string(&self) -> Result<String> {631		let mut str_out = String::new();632		with_default_context(|c, _| unsafe {633			get_string(c, self.0, Some(copy_nix_str), (&raw mut str_out).cast())634		})?;635636		Ok(str_out)637	}638	pub fn to_realised_string(&self) -> Result<RealisedString> {639		with_default_context(|c, es| unsafe { string_realise(c, es, self.0, false) })640			.map(RealisedString)641642		// let store_paths = unsafe { nix_raw::realised_string_get_store_path_count(str) };643		// for i in 0..store_paths {644		// 	let store_path = unsafe { nix_raw::realised_string_get_store_path(str, i) };645		// 	nix_raw::store_path_name(store_path, callback, user_data);646		// }647		// dbg!(store_paths);648		// todo!();649	}650651	pub fn has_field(&self, field: &str) -> Result<bool> {652		let f = init_field_name(field);653		with_default_context(|c, es| unsafe { has_attr_byname(c, self.0, es, f.as_ptr().cast()) })654	}655	// pub fn derivation_path(&self) {656	// 	nix_raw::real657	// }658	pub fn list_fields(&self) -> Result<Vec<String>> {659		if !matches!(self.type_of(), NixType::Attrs) {660			bail!("invalid type: expected attrs");661		}662663		let len = with_default_context(|c, _| unsafe { get_attrs_size(c, self.0) })?;664		let mut out = Vec::with_capacity(len as usize);665666		for i in 0..len {667			let name =668				with_default_context(|c, es| unsafe { get_attr_name_byidx(c, self.0, es, i) })?;669			let c = unsafe { CStr::from_ptr(name) };670			out.push(c.to_str().expect("nix field names are utf-8").to_owned());671		}672		Ok(out)673	}674	pub fn get_elem(&self, v: usize) -> Result<Self> {675		if !matches!(self.type_of(), NixType::List) {676			bail!("invalid type: expected list");677		}678		let len = with_default_context(|c, _| unsafe { get_list_size(c, self.0) })? as usize;679		if v >= len {680			bail!("oob list get: {v} >= {len}");681		}682683		with_default_context(|c, es| unsafe { get_list_byidx(c, self.0, es, v as u32) }).map(Self)684	}685	pub fn attrs_update(self, other: Value) -> Result<Self> {686		let a_fields = self.list_fields()?;687		let b_fields = other.list_fields()?;688		match (a_fields.len(), b_fields.len()) {689			(_, 0) => return Ok(self),690			(0, _) => return Ok(other),691			_ => {}692		}693		let mut out = HashMap::new();694		for f in a_fields.iter() {695			if b_fields.contains(f) {696				break;697			}698			out.insert(f.as_str(), self.get_field(f)?);699		}700		if out.is_empty() {701			// All fields from lhs are overriden by rhs702			return Ok(other);703		}704		for f in b_fields.iter() {705			out.insert(f.as_str(), other.get_field(f)?);706		}707		Ok(Self::new_attrs(out))708	}709	pub fn get_field(&self, name: impl AsFieldName) -> Result<Self> {710		if !matches!(self.type_of(), NixType::Attrs) {711			bail!("invalid type: expected attrs");712		}713714		name.as_field_name(|name| {715			with_default_context(|c, es| unsafe {716				get_attr_byname(c, self.0, es, name.as_ptr().cast())717			})718			.map(Self)719		})720		.with_context(|| format!("getting field {:?}", name.to_field_name()))721	}722	pub fn call(&self, v: Value) -> Result<Self> {723		let kind = self724			.functor_kind()725			.ok_or_else(|| anyhow!("can only call function or functor"))?;726727		let function = match kind {728			FunctorKind::Function => self.clone(),729			FunctorKind::Functor => {730				let f = self.get_field("__functor")?;731				assert_eq!(732					f.type_of(),733					NixType::Function,734					"invalid functor encountered"735				);736				f737			}738		};739740		let out = Value::new_uninit();741		with_default_context(|c, es| unsafe { value_call(c, es, function.0, v.0, out.0) })?;742743		Ok(out)744	}745	pub fn eval(v: &str) -> Result<Self> {746		let s = CString::new(v).expect("expression shouldn't have internal NULs");747		let out = Self::new_uninit();748		with_default_context(|c, es| unsafe {749			expr_eval_from_string(c, es, s.as_ptr(), c"/root".as_ptr(), out.0)750		})?;751		Ok(out)752	}753	pub async fn build(&self, output: &str) -> Result<PathBuf> {754		if !self.is_derivation() {755			bail!("expected derivation to build")756		}757		let output_name = self.get_field("outputName")?.to_string()?;758		let v = if output_name != output {759			let out = self.get_field(output)?;760			if !out.is_derivation() {761				bail!("unknown output: {output}");762			}763			out764		} else {765			self.clone()766		};767		// to_string here blocks until the path is built768		let s = v.builtin_to_string()?;769		let rs = s.to_realised_string()?;770		let drv_path = rs.as_str().to_owned();771		Ok(PathBuf::from(drv_path))772	}773	pub fn as_json<T: DeserializeOwned>(&self) -> Result<T> {774		let to_json = Self::eval("builtins.toJSON")?;775		let s = to_json.call(self.clone())?.to_string()?;776		Ok(serde_json::from_str(&s)?)777	}778	pub fn serialized<T: Serialize>(v: &T) -> Result<Self> {779		Self::eval(&nixlike::serialize(v)?)780	}781782	// Convert to string/evaluate derivations/etc783	// fn to_string_weak(&self) -> Result<String> {784	// 	// TODO: For now, it works exactly like to_string, see the comment for fn force()785	// 	self.to_string()786	// }787788	fn is_derivation(&self) -> bool {789		if !matches!(self.type_of(), NixType::Attrs) {790			return false;791		}792		let Some(ty) = self.get_field("type").ok() else {793			return false;794		};795		matches!(ty.to_string().as_deref(), Ok("derivation"))796	}797	fn functor_kind(&self) -> Option<FunctorKind> {798		match self.type_of() {799			NixType::Attrs => self800				.has_field("__functor")801				.expect("has_field shouldn't fail for attrs")802				.then_some(FunctorKind::Functor),803			NixType::Function => Some(FunctorKind::Function),804			_ => None,805		}806	}807	pub fn is_function(&self) -> bool {808		self.functor_kind().is_some()809	}810}811812impl From<String> for Value {813	fn from(value: String) -> Self {814		Value::new_str(&value)815	}816}817impl From<bool> for Value {818	fn from(value: bool) -> Self {819		Value::new_bool(value)820	}821}822impl From<&str> for Value {823	fn from(value: &str) -> Self {824		Value::new_str(value)825	}826}827impl<T> From<Vec<T>> for Value828where829	T: Into<Value>,830{831	fn from(value: Vec<T>) -> Self {832		Value::new_list(value)833	}834}835836impl Clone for Value {837	fn clone(&self) -> Self {838		with_default_context(|c, _| unsafe { value_incref(c, self.0) })839			.expect("value incref should not fail");840		Self(self.0)841	}842}843impl Drop for Value {844	fn drop(&mut self) {845		with_default_context(|c, _| unsafe { value_decref(c, self.0) })846			.expect("value drop should not fail");847	}848}849850pub fn init_libraries() {851	unsafe { GC_allow_register_threads() };852853	let mut ctx = NixContext::new();854	ctx.run_in_context(|c| unsafe { libutil_init(c) })855		.expect("util init should not fail");856	ctx.run_in_context(|c| unsafe { libstore_init(c) })857		.expect("store init should not fail");858	ctx.run_in_context(|c| unsafe { libexpr_init(c) })859		.expect("expr init should not fail");860861	nix_logging_cxx::apply_tracing_logger();862}863864#[test_log::test]865fn test_native() -> Result<()> {866	init_libraries();867868	let mut fetch_settings = FetchSettings::new();869	fetch_settings.set(c"warn-dirty", c"false");870871	let manifest = format!("{}/../../", env!("CARGO_MANIFEST_DIR"));872	let flake = FlakeSettings::new()?;873	let parse = FlakeReferenceParseFlags::new(&flake)?;874	let (mut r, _) = FlakeReference::new(&manifest, &flake, &parse, &fetch_settings)?;875	let lock = FlakeLockFlags::new(&flake)?;876	let locked = r.lock(&fetch_settings, &flake, &lock)?;877	let attrs = locked.get_attrs(&mut FlakeSettings::new()?)?;878879	let builtins = Value::eval("builtins")?;880	assert_eq!(builtins.type_of(), NixType::Attrs);881882	assert_eq!(attrs.type_of(), NixType::Attrs);883	let test_data = nix_go!(attrs.testData);884885	let test_string: String = nix_go_json!(test_data.testString);886	assert_eq!(test_string, "hello");887888	Ok(())889}890891// pub struct GcAlloc;892// unsafe impl GlobalAlloc for GcAlloc {893// 	unsafe fn alloc(&self, l: Layout) -> *mut u8 {894// 		let ptr = unsafe { GC_malloc(l.size()) };895// 		ptr.cast()896// 	}897// 	unsafe fn dealloc(&self, ptr: *mut u8, _: Layout) {898// 		// unsafe { GC_free(ptr.cast()) };899// 	}900//901// 	unsafe fn realloc(&self, ptr: *mut u8, _: Layout, new_size: usize) -> *mut u8 {902// 		let ptr = unsafe { GC_realloc(ptr.cast(), new_size) };903// 		ptr.cast()904// 	}905// }906//907// #[global_allocator]908// static GC: GcAlloc = GcAlloc;